Modern telecommunications systems typically utilize digitally encoded data instead of analog data. If analog data is used, it may be converted to digital data for the purposes of switching the data between conducting media. Switching of data occurs at large telecommunications switches, which may receive and process hundreds or thousands of data channels.
One method of carrying a large number of data channels comprises encoding the data into an optical signal. A single optical fiber has greater usable bandwidth, occupies less physical space, and may have a lower cost than most electrical conductors. Nevertheless, the data encoded into the optical signal carried by an optical fiber must be converted into data encoded into an electrical signal before the data can be processed for use in telecommunications applications.
Because the data transmitted over an optical fiber is received and transmitted at high speeds, it is necessary to precisely control the reception and transmission of data at the interface between the optical and electrical systems. If the reception and transmission of data at the interface between the optical and electrical systems is not precisely controlled, then errors may be introduced into the data that can cause loss of data, interruption of data channels, and failure of the data transmission system.